This invention relates to compositions and methods for treating subterranean formations, in particular, oilfield stimulation compositions and methods using essentially non-crystalline gelling agents. The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Transport of particulate solids during the production of hydrocarbons from a subterranean formation is a continuing problem. The use of sand control methods such as stand alone screens, gravel packs, and frac and pack treatments is a common practice to mitigate, minimize or prevent the return of solids to surface. The transported solids can plug, erode or cause significant wear in hydrocarbon-production equipment during recovery. The solids can also clog or plug the formation or wellbore, thereby limiting or completely stopping fluid production. Further, the transported particulates must be separated from the recovered hydrocarbons, adding further expense. The source of transported particulates may be the formation or particulates added such as fines present with a proppant or produced from partially crushed proppant.
Presently known fines migration techniques suffer from a few drawbacks. Present fines migration control treatments are not positioned deep into the formation to control fines where they are generated and where the pressure drop disturbing the fines is relatively low. Many fines migration techniques are provided as a pre- or post-fracturing or gravel pack treatment (e.g. the FinesLOK® service, registered to Schlumberger Technology Corporation), or as a treatment that fixes fines within a propped fracture or a gravel pack (e.g. the Sand Wedge® service, registered to Hallburton Energy Services). The latter prevents fines migration into the wellbore, but allow the formation fines to migrate into the fracture or against the gravel pack before they are fixed, damaging the permeability of the fracture and/or the gravel pack. Further, present fines migration control treatments are presented in low viscosity fluids subject to fluid fingering and highly non-uniform distribution of the fluid into the formation. Present fines migration fluids utilize additional treatment steps and fluids from a primary fluid treatment, increasing costs, complicating the treatment schedule, and increasing the physical footprint of the treatment equipment. Therefore, further technological developments are desirable in this area.